Chapter XI · CALLOSITAS

Derivation. The word callositas is derived from the Latin “callus,” meaning horn.

Synonyms. Callus, callosity, callous, tyloma, tylosis.

Definition. Callositas, or callouses, are a thickening of the epidermis, usually found on the plantar surface of the foot. They also occur on the dorsum of the toes, and are found on the hands of mechanics who continuously use hand tools involving pressure on the parts. Coachmen develop callouses between their fingers on account of the manner in which they hold the reins while driving. In rare instances, women have been known to have callouses on their hips, due to the pressure of the steel in their corsets, and cavalry men who sit in the saddle for long periods develop callous on the parts exposed to irritation.

Symptoms. Callosities are composed of variously sized areas of yellowish or grayish, horny excrescences of epidermic cells. They are hard, dry and horn-like, thicker in the centre of the growth and gradually becoming thinner at the periphery. There is no sharp line of demarcation between a callous and the surrounding skin, such as is found in helomata, but the thickened cuticle gradually blends with the surrounding skin.

Etiology. A callosity is the result of an irritation of some form and is nature’s way of protecting the delicate structures beneath the skin from the direct pressure or friction to the parts. The outer layers of the skin become thickened and act as a buffer, which absorbs shock and prevents inflammation and tissue destruction. When found on the soles of the feet, callouses are due to standing or walking in improper footgear. The ball of the great toe is a very common site for callosities; also the region over the heads of the metatarsal bones, due to high heels which force one to walk directly on these parts without equal weight distribution, is subject to them.

Callosities may occur as the result of chronic skin lesions such as eczema, psoriasis, lichen planus and ichthyosis and after the prolonged use of arsenic.

Callosities occurring on the dorsum of the toes are caused by the pressure of the skin against the top of the shoe. The parts beneath the callous at this point usually show the presence of bursitis, which causes a swelling and subsequent pressure on the skin.

Pathology. The changes that take place in the formation of callosities are the same as those which arise in heloma, except that the deeper layers of the epidermis and the true skin are not affected unless accidentally infected or injured.

There is no inflammation present except in cases of infection or injury. The upper layers of the epidermis are the only ones involved, and the condition is really a physiologic rather than a pathologic one. It is more of a protection than a true hypertrophy. The overgrowth may continue to a greater extent, and then even helomata may develop.

Diagnosis. The callosity is yellow to grey in color and is composed of a horn-like mass of epidermic cells. It is easily distinguished from an heloma in that there is no nucleus present, and the part is not severely painful on pressure. It may be mistaken for some of the chronic skin lesions, previously mentioned, but the skin eruption presents a scale or crust which readily peels off, en masse, leaving the bare rete Malpighii exposed. The callosity comes off in layers and, as the deeper structures are reached, a healthy pink color is noticed.

Prognosis. A change in occupation or a change of footgear often results in the disappearance of this condition. Unless the direct cause is removed there will be a recurrence, which is an indication that the part again needs protection and care. Persons who have been accustomed to standing or walking for protracted periods of time, such as policemen, floor walkers, etc., soon lose the callouses they developed, after they change their occupation.

Treatment. If the growth becomes thick enough to cause discomfort, it may be easily removed, by softening it and then scraping or paring it. The foot may be soaked in an alkaline foot bath composed of one-half ounce of sodium bicarbonate to two quarts of hot water, or painting the part with a dilute solution of potassium hydroxide (caustic potash), 5%, several applications every few minutes, the softened area being scraped away after each application. Salicylic acid plaster, 25%, placed over the affected area and allowed to remain in contact for forty-eight hours, will usually loosen the redundant mass. If the callosity appears over the head of the first or fourth metatarsal bone, mechanical adjustment should be made, whereby the pressure in walking is thrown upon the entire surface of the anterior part of the foot. Pads of felt or buckskin, properly skived and fitted, will accomplish this result.

Care must be taken that too much of the induration is not removed when treating this condition. As previously stated, the calloused mass acts as a protective for the parts beneath and is nature’s way of preventing serious trouble, and if too much is removed, pain will be experienced when the foot is used in walking. If this should occur, the part should be painted with tincture of iodine, 4%, and covered with moleskin or adhesive plaster. If an abrasion has been made, it is important to dress the part with an antiseptic, followed by a stimulating agent, all of this to be covered with a cocoon dressing or a lint shield.

Where callosities are caused by a displacement of the anterior metatarsal arch, or by any of its bony constituents, the bony lesion must be corrected before the callosities will respond to treatment.